Data transmission is an important technology widely used in electronic devices. Almost every computer, cellphone, or tablet devices has adopted I/O (input/output) ports, such as a USB (Universal Serial Bus), to transmit data from and to an external device. The external device may be an external storage device, a mouse, a camera, or a smart device such as a computer. As the performances of these electronic devices are constantly improved, the I/O ports therein are required to support faster and faster data transmission. Sometimes such requirement means a new design of the I/O ports. For example, compared to USB 2.0, which includes only one pair of differential data transmission lines, a new generation USB 3.0 includes three pairs of differential data transmission line. But upgrading hardware is expensive. And newly designed I/O ports generally are only applicable to newly manufactured device. Manufactures are will generally unable to recall and upgrade electronic devices. Thus an alternative and cheaper option to achieve a higher data transmission speed may be to increase I/O ports' transmission efficiency based on the old designs.